Achievement of an erection is a natural process experienced by all men. In recent years considerable research has been performed on the erectile process. These include studies on the anatomy of the penis, the physical events associated with an erection, and new diagnostic tests.
The penis is composed of three cylinders. On the under side, there is a cylinder called the corpus spongiosum which contains the urethra and permits the flow of urine and ejaculate. Although this cylinder becomes distended during an erection, it does not become rigid. The remainder of the penis consists of two larger cylinders called corpora cavernosa. These are paired structures which occupy a majority of the space of the penis. During an erection, these cylinders fill with blood to produce firmness and rigidity. Each corpora is surrounded by a thick fibrous covering called the tunica albuginea. This covering has limited elasticity and distensibility. When the penis fills with blood and the corpora reach full size, the tunica albuginea will stretch to its limit and the penis becomes rigid.
Within the corpora, there are smooth muscle fibers, arteries, nerves and veins. These structures interact to produce an erection and 4 physical events occur as follows:
1. A stimulus (touch, feel, etc.) must be transmitted through the nerve endings within the penis to release a chemical known as a neurotransmitter.
2. This chemical in turn produces a dilation of the central artery of the corpora leading to an increase in arterial blood within the corpora.
3. The smooth muscle strands within the corpora relax to enable complete filling.
4. As the corpora distend and reach the elastic limit of its outer covering (tunica albuginea), the penile veins are compressed which limit the outflow of blood from the penis during erection.
X-rays of the penis known as cavernosography have demonstrated that approximately 60-80% of impotent men have "venous leakage." Another 10% of potent men also have minimal "venous leakage." In these men, the venous system does not compress during maximum filling which permits excessive drainage of blood from the penis leading to a premature and undesirable softening or detumescence. Heretofore, various types of ring appliances or devices such as, for example, disclosed in U.S Pat. Nos. 3,455,301, 3,461,863, 3,636,948, and 4,539,980 have been proposed which encircle the penis to prevent failing erections by restricting the return veinal flow. These prior art ring-like devices have been known as "cock rings."
Research on the erectile process has demonstrated that while the constrictor rings used in the past may be beneficial and reasonably effective for men with "venous leakage," they may not be safe because of possible penile strangulation, i.e., complete compromise to arterial blood flow. In U.S. Pat. Nos. 4,203,432 and 4,723,538, penile constriction ring devices for the treatment and alleviation of impotence in males are described which include some provision for adjusting the degree of constriction and/or for removing all constriction after a period of time. Such devices, however, are somewhat complex in construction and require significant manipulation by the user to be reasonably effective for their intended purpose.